'Impossible' and Controversial EM Drive Can Get Us to the Moon in Four Hours

The physics-defying EM Drive has been touted as a futuristic technology that would be capable of achieving near-relativistic speeds. After a seemingly successful test by NASA Eagleworks earlier this year, German scientists have confirmed this week that the engine actually works. Although many experts are skeptical of these results, if they are proven to be true, then we could potentially build spaceships that would get us to the Moon in only four hours.

When NASA first proposed the engine, it seemed to many to defy the laws of physics and the law of the conservation of momentum. According to NASA, the engine would directly convert electromagnetic energy into thrust by colliding microwaves within a closed container, bypassing the need for propellant. But physicists criticized this model on the grounds that the expulsion of propellant is necessary in order to balance the spacecraft's momentum during acceleration.

Then, in April of this year, a NASA engineer conducted a test in a vacuum, and was unable to falsify the results. This not only addressed some of the initial concerns, but more accurately reflected the conditions the engine would encounter in space. And this week, Martin Tajmar, a professor and chair for Space Systems at Dresden University of Technology claimed that his experiment, also within vacuum conditions, showed the engine produces thrust.

"Our test campaign cannot confirm or refute the claims of the EM Drive but intends to independently assess possible side-effects in the measurements methods used so far," the authors wrote in the study. "Nevertheless, we do observe thrust close to the actual predictions after eliminating many possible error sources that should warrant further investigation into the phenomena. Our measurements reveal thrusts as expected from previous claims after carefully studying thermal and electromagnetic interferences. If true, this could certainly revolutionize space travel."

If these results turn out to be accurate, then the engine would certainly revolutionize space travel as we know it. The engine would be capable of producing thrust thousands of times greater than a standard photon rocket, and would have the ability to get us to Mars in only 70 days and to Pluto within 18 months, as opposed to New Horizons's nine-year journey.

But many experts are coming out of the woodwork to express doubts about the much-vaunted "confirmation" of the results. Many note that this is simply a lack of falsification, and that there is not nearly enough evidence to assume that the seemingly impossible engine actually works.

"The microwave cavity thruster as set-up by Tajmar continues to violate momentum conservation and thus does not work as advertised," Eric W. Davis, a Senior Research Physicist at the Institute for Advanced Studies in Austin, told io9. "Why he doesn't simply capitulate to that very obvious well-known issue in this particular application of electromagnetic physics is unknown to me. Maybe he is playing the role of the 'supportive skeptic' that wants to test this incredible outlandish EM propulsion claim for himself to see what it does."

Several researchers also noted specific problems with the study itself; Davis claimed that his instrument for measuring thrust was not accurate in the high heat that was generated in the experiment, and that the experiment doesn't account for the violation of the law of the conservation of momentum, which would cause legitimate scientific journals to reject the paper when it's peer-reviewed.

CalTech physicist Sean Carroll was significantly more emphatic about the project as a whole:

"My insight is that the EMDrive is complete crap and a waste of time," said Carroll. "Right there in the abstract this paper says, 'Our test campaign can not confirm or refute the claims of the EMDrive', so I'm not sure what the news is. I'm going to spend my time thinking about ideas that don't violate conservation of momentum."